The use of an RP-HPLC-UV method for the analysis of oxcarbazepine in the presence of its preservatives; stability studies and application to human plasma samples

A simple, sensitive, selective, accurate and precise method was developed and fully validated for determination of oxcarbazepine (OXC) in presence of their preservatives and determination of oxcarbazepine (OXC) in human plasma. A reversed phase liquid chromatography (RP-HPLC) with UV detection techniques were applied for separation and quantification of studied drug OXC. Successful separation of the drug from methyl paraben (M.P.), propyl paraben (P.P.) and potassium sorbate (P.ST.) was achieved on a Kromasil C18 column (5 μm particle size, pore size 300 Å, l × I.D. 250 × 4.6 mm). The mobile phase that contain aqueous 0.05M potassium dihydrogen phosphate buffer (pH 7): acetonitrile, (50: 50, %v/v). The method was linear over concentration ranges 5.0–50 μg mL−1 for OXC. Bioanalytical validation of the developed method was carried out according to US-FDA guidelines and revealed a good linear relations over a range of (5.0–50), (0.5–10), (0.05–0.15), and (1.0–10) μg mL−1 for OXC, M.P, P.P, and P.ST, respectively, with a correlation coefficient (R2) of more than 0.999. Limit of detection (LOD) were 1.15, 0.03, 0.01 and 0.04 μg mL−1 for OXC, M.P, P.P, and P.ST, respectively, Intra and inter-day precisions, calculated as percentage relative standard deviation (% RSD), were lower than 2.0%. The developed method can be applied for routine drug analysis, therapeutic drug monitoring and bioequivalence studies through the analysis of plasma samples taken from blood bank.